Abstract : For the sake of planet conservation, it is often asked to consumers to modify their habits, especially regarding food consumption. For more sustainable decisions, consumers may for instance buy and consume products that are less costly in terms of greenhouse gas emissions and also that include plant-based proteins instead of animal-based proteins. Nevertheless, it is not clear whether consumers are able to make the necessary substitutions and it remains unknown how consumers value the products when greenhouse gas emissions are constrained. We first evaluate consumers’ willingness-to-pay (WTP) for the set of food products that constitute two meals of a typical day when they have no constraint. Then, we elicit consumers’ willingness-to-pay when they are constrained to reduce the sum of greenhouse gas emissions of their products by 20%. Therefore, we evaluate the value consumers attribute to food consumption that satisfies objectives of sustainability and are able to study substitutions between products.